<div id="controls">
  <button id="roNoBox">ResizeObserver without box</button>
  <button id="roPolyfill">ResizeObserver polyfill</button><br />
  <label for="height">height</label>
  <select name="height" id="height">
    <option value="heightAuto">auto</option>
    <option value="heightHundred">100%</option>
    <option value="height200">200px</option>
  </select>
  <label for="width">width</label>
  <select name="width" id="width">
    <option value="widthAuto">auto</option>
    <option value="widthHundred">100%</option>
    <option value="width200">200px</option>
  </select>
  <label for="padding">padding</label>
  <select name="padding" id="padding">
    <option value="padding0">0</option>
    <option value="padding10">10px</option>
    <option value="padding50">50px</option>
  </select>
  <label for="border">border</label>
  <select name="border" id="border">
    <option value="border2">2px</option>
    <option value="border10">10px</option>
    <option value="border0">0</option>
  </select>
  <label for="boxSizing">boxSizing</label>
  <select name="boxSizing" id="boxSizing">
    <option value="boxSizingBorderBox">border-box</option>
    <option value="boxSizingContentBox">content-box</option>
  </select>
  <label for="display">display</label>
  <select name="display" id="display">
    <option value="displayBlock">block</option>
    <option value="displayNone">none</option>
  </select>

  <button id="start">start</button>
  <span>Detected resizes: <span id="resizes">0</span></span>
</div>
<div id="stage">
  <div>
    <div id="target">test</div>
  </div>
</div>
